The present invention relates generally to a heat dissipation device for edge-mounting to a circuit board to remove heat from a heat generating electronic device mounted to the circuit board, and in particular to a heat dissipation device comprised of a top-and-bottom fan structure for efficiently removing heat from the heat generating device and at the same time cooling both sides of the circuit board.
A lot of electronic devices, such as central processing units, generate heat when they are in operation. The heat must be timely removed otherwise the electronic device malfunctions due to improper high temperature caused by the heat. Fans are commonly used to generate air streams for carrying heat away from electronic devices that are mounted on a circuit board. However, mounting a fan on a circuit board not only occupies real estate of the circuit board, but also increases the height of the electronic device. This is against the trend of minimization of electronic devices. Thus, fans are positioned remote from the electronic device from which heat is to be carried away and are thermally coupled to the electronic device by heat pipes. This, although reducing the overall height of the electronic device, still requires a large foot print on the circuit board for mounting the fan.
In addition, with the increasing number of electronic parts mounted on both sides of a circuit board the surrounding air is getting hot caused by heat radiation of the electronic parts during the operation of the circuit board. This is adverse to the heat dissipation of the electronic device.
Thus, it is desired to have a heat dissipation device that overcomes the above problems.
An object of the present invention is to provide a heat dissipation device comprised of a top-and-bottom fan structure that is mounted to an edge of a circuit board for reducing the footprint taken by the heat dissipation device.
Another object of the present invention is to provide a heat dissipation device comprised of two fans that are respectively located above and below a circuit board for causing air flows through upper and lower sides of the circuit board.
A further object of the present invention is to provide a heat dissipation device comprised of a multiplicity of fans for efficiently and effectively removing heat from a heat generating device.
To achieve the above objects, in accordance with the present invention, there is provided a heat dissipation device to be mounted to an edge of a circuit board for removing heat from an electronic device mounted on the circuit board. The heat dissipation device comprises a contact pad made of thermally conductive material and positioned on the electronic device. A multiple fan structure comprises a casing defining an air passage in fluid communication with a front opening to which a heat sink is mounted and top and bottom openings to which top and bottom fans are respectively mounted. Heat pipes extend between the contact pad and the heat sink. Air is sucked into the casing by the fans and flows through the air passage to the heat sink for carrying away heat from the heat sink. The casing is mounted to an edge of the circuit board with the top and bottom fans respectively located above and below the circuit board. Side openings are defined in the casing for discharging air into upper and lower sides of the circuit board for simultaneously cooling the upper and lower sides of the circuit board.